In the prior art, different wire thread inserts for mounting into a receiving thread of a component are known. They are for example described in U.S. Pat. No. 2,363,789, EP-A-0 140 812 and EP-A-0 157 715. Consistently, the outer diameter of the cylindrical walls of the wire thread insert has to be chosen somewhat larger as the outer diameter of the receiving thread of the component. Therefore, the mounting of the wire thread insert into the receiving thread of the component has to occur by means of a diameter reduction of the wire thread insert. In this way it is ensured that a tight fit of the wire thread insert is achieved by means of the elastic re-deformation of the wire thread insert after installation in the receiving thread.
For facilitating the driving in of the wire thread insert into the receiving thread, a half winding at the end of the cylindrical coil of the wire thread insert is retracted or moved radially into the inside in known manner (EP-B1-0 228 981). The smallest outer diameter of the retracted section of the wire thread insert shall be almost equal to or somewhat larger as the corresponding outer diameter of the receiving thread in the component. Further, at this known wire thread insert, the wire cross-section is tapered at the end to facilitate the driving in of the wire thread insert into the receiving thread and to avoid damages of the thread bore in the component.
Different embodiments of wire thread inserts are also disclosed in EP-B1-0 983 445. A wire thread insert consists of a cylindrical coil with a plurality of helically wound windings. A first winding of this cylindrical coil leads to a mounting tang protruding linearly radially into the cylindrical coil. By means of a suitable installation tool, this mounting tang is grasped and thereby, the wire thread insert is screwed into the receiving thread of the component. After the installation has been completed, the mounting tang is removed by breaking-off the mounting tang in the first winding with the aid of a predetermined breaking point. In this way, a receiving thread with a continuously screwable wire thread insert results.
DE 1 016 066 B discloses a locking screw at which a wire thread insert is fastenable. For this purpose, the locking screw has a transverse slot at a front end in which a radially inwardly bent driving tang of the wire thread insert can be received. To be able to remove the locking screw from the wire thread insert, an inlying channel is provided in the locking screw which ends at the transverse slot. A pin can be inserted into this channel by means of which the driving tang can be pressed out of the transverse slot. At this, the driving tang is neither excessively deflected, broken or permanently deformed. Subsequently, the locking screw can be removed from the wire thread insert.
DE 10 2010 050 735 describes different alternatives of a wire thread insert with redressable but not removable tang. The tangs serve for installing the wire thread insert in a component opening with thread. After installation, the tang is redressed into the circumferential shape of the wire thread insert without obstructing later the screwing-in of a threaded bolt into the wire thread insert. The redressing occurs by means of an installation tool having a compressing blade. The compressing blade exerts a force onto the free front end of the tang and redresses it thereby. For facilitating the redressing, a bending portion between coil and tang of the wire thread insert comprises a tapered notch or a moving notch. The moving notch serves at the same time as tapering in the bending portion and as installation aid for the wire thread insert into the component opening.
Starting from the known wire thread inserts with redressable and not removable tang, it is the technical object of the present invention to provide an alternative and technically simple and resilient installation tool and an alternative installation method by means of which the wire thread insert is installable in a component opening with thread.